Guide apparatus for centrifugal blowers and pumps



A. BCHI Filed May 27, 1941 4 Sheets-Sheet 1 l l I lill/lll! l mw v' Feb. 16, 1943.

GUIDE APPARATUS FOR CENTRIFUGAL BLowERs AND PUMs Feb. 16, 1943. A. BUcHl 2,311,024

GUIDE APPARATUS FOR CENTRIFUGAL BLOWERS AND PUMPS 4 Sheets-Sheet 2 Filed May 27, 1941v A. BcHl Feb. 16, 1943.

GUIDE APPARATUS FOR CENTRIFUGAL BLOWERS AND PUMPS Filed May 27, 1941 4 sheets-'sheet s Feb. 16, 1943. A BUCHI v 2,311,024

GUIDE APPARATUS FOR CENTRIFUGAL BLOWERS AND PUMPS Filed May 27, 1941 4 sheets-sheet 4 33 3&3/ [lll I* lllllll Patented Feb. 16, 1943 OFFICE GUIDE APPARATUS ron CENTRIFUGAL BLowEas AND PUMPS Ain-ea michi, winterthur-,switzerland Application May 27, 1941, Serial No. 395,480 In Switlerland March 8, 1941 20 Claims. An object of this invention is to provide guide ,means for fluids emerging from the rotor o! a centrifugal pump which is of such shape and construction as will convert the velocity of the iluid into pressure in the most efflcient manner.

A further object of the inventionls to provide the guide means with passages having outwardly increasing cone-shaped diffuser portions toward the inner ends thereof, the axes of said portions being straight and the length ofsaid straight conical portions being as great as possible within constructional limitations.

A further object of the invention is to provide the outer portions of the passages of the guide means, outwardly beyond the straight conical portions. with such a shape as will continue the diiuser action in an emcient manner and will guide the fluid into the outer space which receives the uid in a smooth and eiicient manner.

Further objects of the invention are to provide the correct shape of the passages throughout their entire extent and to position the guide means at the most favorable position relative to the impeller.

A still further object of the invention is to make the collector casing of such shape or proportions that thevelocity of the iluid at its outlet is less than at its inlet, and to make the discharge areas of the nuid passages of the diffuser of correct size to leadthe fluid into the outer part of the collector at the same velocity as at the outlet of the collector.

Other objects and advantages yof the invention will be apparent from the following detailed description of some embodiments of the invention which are illustrated in the accompanying drawmgs. I

In the drawings, Figure 1 is an axial sectional view on the line I-I of Fig. 2 of a centrifugal pump or blower having a guide apparatus in accordance with this invention.

Figure 2 is an elevation of one half of the blower of Fig. 1, the separation being on the lineII- II of Fig. 1. Q

Figure 3 is a view similar to Fig. l of a modified embodiment of the invention, the section being on the line III-III of Fig. 4.

Figure 4 is a view similar to Fig. 2 of the embodiment represented in Fig. 3, the separation being on the line IV-IV of Fig. 3.

Figure 5 is an elevation of one of the halves of the guide apparatus according to a further modication.

Figure 6 is an axonometric view of the vguide f channels.

Figure 7 is a fragmentary view of a further modied form of guide apparatus.

Figure 8 is a section through a multi-stage blower or pump.

Corresponding parts in the various ngures are identiiled with the same reference numerals.

Referring to Figs. 1 and 2, I designates the rotor of the pump or blower. This rotor can be of any known type and does not form a part of the present invention. The rotor is keyed to the driving shaft 2 which may be driven by an electromotor 3. A closed collector casing 4, Il' surrounds the rotor and contains the guide apparatus 5, 5' according to the invention. This guide apparatus comprises for example eight guide passages 6 successively disposed around the rotor I. The guide passages are composed of receiving channels 'I to which succeed in the direction of ilow of the iluid, ilrst straight guide passage portions 8 widening on all sides, so as to have a gradually increasing sectional area, and then outer guide passage portions 9 having straight lateral walls 30, 3| extending transversely to the driving axis 2 in the same direction as the lateral walls 26, 21 of the passage portions 8, and walls I0 and II which are curved in the direction of rotation of the rotor. These curved walls have radii of curvature I2 and I3 which, at the entrance to the passage portions 9, are equal to at least three times the diameter of the guide passage at this place. It is advantageous for obtaining an undisturbed now,

in -the guide passages that the circles corresponding to the radii o1' curvature I2 and I3 are tangentially contacting with the Walls of the passages. Owing to the particular described shape of the guide passage portions 8 and 9, the partitions or blades I8 intermediate these passages are formed with unusual and irregular shape with respect to guide apparatus oi. known design, the cross section in the middle portion of these partitions being relatively thick.

'I'he iiuid discharged from the rotor I is irst received in acylindrical chamber I I surrounding the rotor and then passes through the receiving channels 1 wherefromit enters into the straight-walled widening guide passage portions 8. Owing to the-gradually increasing sectional area oi' these portions, the velocity oii the iluid at the entrance I5 to the guide passages is transformed with high enlciency into pressure. During the now of the fluid through the passage portions '9, a reduction of velocity also takes place in these portions Aowngrto their gradually increasing sectional area, and accordingly a furtransformation in the entire passage. A lcrease of eiflciency in the passage portion 9 can 30 ther increase of pressure is obtained. However,

since the passage walls I and II deflect the -portions 9, and th'e rate of transformation into pressure is proportional to the difference of the squares of velocity, and supposing that in each of the two passage portions 8 and 9 a transformation of velocity to one half of its value takes place, that is to say when the sectional area at the entrance I5 is one half of the sectional area I6 at the end of the straight passage portion 8, and when th'e sectional area I6 is one half of the sectional area at the Apassage outlet l1, then the theoretical production of'pressure in the straight portion 8*'wi1i be four times higher than in the curved portion '9. Forthis reason the decrease of the eiliciency oftransformation in the portions 9 has no great influence on the total efficiency of The de- 'still 'be reduced when the tangentially guiding walls I9 and I I are provided, at least in proximity of the straight passage portion ii, with a great radius of curvature as compared with the diameter of the passages, this radius being for example and according to the invention not less than three or four times th'e diameter of the passage at this place. In order to avoid as much as possible the presence of diifer'ent pressures along the passage walls Ill and II the radii of curvature I2 and I3 at the inner and outer side vof the portion 9 are, in accordance with the invention, substantially of equal length. In this case the same effects of twist will be produced at the internal and at the external sides of the curved portion. The width of th'e channels between the curved walls can be kept equal throughout, or it can be gradually increased in the direction of the ow `or the uid.

The fluid discharging from the guide passages enters into the collecting chamber I9. The sectional area of the outlet II of the passages is such that the transformation of velocity in the portion 9 is carried out until the velocity of the fluid entering the chamber I9 is equal to or slightly higher than the velocity of conduction at the outlet 2| of the collector casing. In the latter case the straight portion 20 of the collector outlet in Fig. 2 has a gradually widening sectional area so as to form a diffuser. The different guide passages 6 can be provided, in the direction of rotation and towards the outlet of the collector chamber I9, with successively greater outlet areas I1, for example in such manner that the pressure losses at least, resulting in the chamber I9 between two successive passage outlets I1, are compensated by the higher velocity of the fluid discharging from the preceding passage. however possible to make the outlet areas I1 of the passages all of the same size, so that in each passage 6 about the same transformation of velocity takes place and accordingly the reaction of the fluid flowing through the different passages is about the same over the entire circumference of the rotor I.

In Figs. i and 2 the collector casing 4 is inte- 60 passage portions.

75 the passage portion 8'.

gral with the walls of the guide device 5, 5', and the casing 4,` 4' and guide device 5, 5 are formed of two halves, the entire apparatus being sepa.- rated -along a median plane extending trans- 5 versely to the driving axis 2, so that the two portions 4, 5 and 4', 5' are symmetrical with respect to the plane of separation. These two rzagrtions are secured together by means of screws 10 The modification according to Figs. 3 and 4 differs from the previously described example particularly by the fact that the collector casing 4, 4 is unsymmetrical with respect to the transverse median plane passing through the rotor I.

The portion 4 of the casing as seen in Fig. 3 projects much more towards the right side of the median plane than the portion 4 projects towards the left side of this plane. However, the receiving channels 'I and guide passages 8 and 9 are completely symmetrical with respect to the median transverse plane of the rotor I, in order that no secondary flows are created during the actual velocity transformation which would resuit in pressure losses. The laterally projecting .25 portion of the casing can be placed on one or the other side of the4 median plane according to the available space in each specific case.

In this modification, the area of the outlet 2I of the collector casing is not enlarged with respect to the cross sectional area of the casing at 20; the vvelocity transformation in the guide passage portions 9 is carried out in such manner that the velocity at the passage outlets I1 isv reduced to the velocity of conduction at the collector outlet The receiving channels 1 surrounding the rotor I are formed with external and internal walls 23 and 24 of such a shape that the fluid entering into the straight passage portions 8 is guided as much as possible in a symmetrical manner with respect to these portions, for exsecured to each other by screws 25 traversing the thickened portions I8 of the partitions or guide blades between the passages 6. The sectional areas of flow of the receiving channels 1 and of the guide passage portions 8 and9 are in Fig. 3

5() also of trapezoidal shape as in the example of Fig. 1. These sectional areas of flow could also have another shape, such as substantially rectangular, oval or circular.

The sectional areas of flow of the receiving channels I could increase towards the entrance of the guide passage portions 8, in such" manner that already a transformation of velocity into pressure is taking place in the receiving channels before the fluid enters into the straight guide A transformation is also effected already in the cylindrical chamber I4 surrounding the rotor, because this chamber too has an increasing sectional area in the direction of flow.

In the modification according to Fig. 5 the guide passage 6 situated closest to the outlet 2| of the collector chamber I9 is arranged so thatA the axis of the conically widening passage portion 8' extends substantially parallel to the axis of the discharge tube 20. Instead of curved passage portion 9 with which the remaining passages 6 are provided, the portion 9 is also of straight conical shape and gradually widening on al1 sides, the angle of opening being the same as that oi' The gradual increase of 2,811,034 3 aectixnlareatllwuiheoutletaeennll'haa nelsllandll',rcspecuvely,tothenextfollow mhantethattheveloeityotthenuialeavinx inchnnellmlmdlrcspectlvely. Thesechlnthenmsel'iseamltouavelncltynumun nasnhepmvmedwithmudmgbladesmu'- thediachargepipell. 'meco-marcan `'hiena-sauroacorreetleiuiingoftheiluidto Il'and Il oftheportknl'alcorltheaame 5 thei'ollowingimpellersl'andi". Thechamber hun ",howevel-,isbuiltasasplralcasingwitha other-gundam This om; sectionuptoitsexitsection theldvmtagethatthciluiddlldllrlmghm 2i". tbispangemmtnotbecaredaroundtheen- Thesuldeanpamtus aceordingtotheinventirecircmntermceoftheeollectorcuingcmor-10timoil'erstheadvantlge.thatinspiteofafa dertorelchthecollectordhclnrnllll. vorablearrangementofthesuidepassasetransmihavlewontheextermlsldeotthe formingthevelocityintopressure,acommon sukledevlcewhmtheoutecaslngwnllism' collectorcasingnotrcquiringatoogreatdiampoaedtobehmkmam. 'rhepartimlarslnpe eternbeused. Thenumberofsulde ottheguldelllallzecanbe -;1quitewell. 15 cannaturallybeotherthaneightasrepresmted, mgm m. oisnehaplsbutinhasprovedthataredueednumsageshonplainlyhowthemacelimitedbythe beroi'plssagesbetweenaboutilvetoten,inspite reccivlngchannels'loftnpeaoidalshapeis wldof favorable conditions of ilow, requires the cninginthedhectionotilowoftheiluiduntil smallestcollectorcasing. Owingtoseparathn thesectionalamllwheretheiluideutersinto zoofthepartsl,5andl,5'ltismoreoverpossithe straight conically widening passage portion ble, to cut olf the joining faces more or less on asthelateralwalls26and2`loftheportionl,

wha'easthewallsllandlloftheportioniare mlrvcdrelativelytoaxlsofthe portion l, also alreadydescrlhed.

AsitisseenparticularlyfromHg.6,asalient feature of the invention is the arrangement of sents guideplssagesin'whichthe radilofcurvatureofthecurvedwalls Il'and Il ofthepassageportions l have dlifenmt lengths, such as for example indicated by the radii I2, Il, I!" and' I3, I3', Il". The radii of curvature am chosmsotlnttheyarethegreaiestinproximityofthesectionalarea liandthen'enlydeelrweasetowardstheoutletarwca ll. Thisarrangement offers the advnntagethatthe direciiminwhichtheuidfnmthemrtlet arealldiifersaslittleaspoiblefromthegeneral direetirofilowinthecollectorchamber Ilandthattheextemaldiameterofthecollcctorcasinglcanbemadesmaller.

lilgureshowsablowm'orpump vinaxialsection. I, l', Warethethreerotors orimpelleraandi,i',i"aretheguide which surmrmd the impellers. Il, Il", Il" are the collecting chambers for the tluidfromthezllideti'and I". Fromtbechambers Ilandll'theiluid willbeconductedthroughradialS-shapedchana lathe in order to obtain a proper iltting width of the guide device for a given width of the rotor.

Although I have shown particular embodiments of my improved guide apparatus for rotary blowers and pumps, I do not desire my invention to belimited to the particular arrangements disclosed, and I intend in the appended claims to cover all modications which do not part from thespirit and scope of my invention I claim: i 1. In a centrifugal blower or pump, the combination with a rotor, of guide apparatus surrounding the rotor, said guide apparatus includi118 8 plurality of guide passages, a plurality of receiving ychannels for directing the iluid discharged by the rotor to the guide passages, and

an outer collector casing common to all guide es for receiving the ilud discharged therefrom. each of said guide passages being composed of an inner Straight walled funnel-shaped portion the cross sectional area of whichgradually increases in the direction of flow, and of an outer portion joining said inner portion, said outer portion having lateral straight walls extending hansverselytotheaxisofthe rotorandinthe same direction as the corresponding straight walls of the inner portion, and inner and outer walls curved toward the direction of rotation ef the rotor to direct the iluid from the outer guide passage portion into the saidcollector casing.

2. In a centrifugal blower or pump, the combinationwitharotonofguideapparatussurmonding the rotor, said guide apparatus including a plurality of guide receiving channels for chargedbytherotortotheguideand anoutercollcctorcasngcommontoallguide es for the iiuid discharged therefrom, each of said guide passages being composed of an inner straight walled flmnel-shaped portion the cross sectional area of increases in the direcon of flow. and of an outer portionioinngsaidinnerportionandhavinga gradually sectional area in the direction of ow, said outer same direction as the corresponding straight walls of the inner portion, and inner and outer walls curved .toward the direction ofrotatiouoftherotortodirectthe fluid from the outer guide passage portion into the said collector casing.

3. In a centrifugal blower or pump, the comdirecting the llid diswhich gradually t from, each of said guide o outer walls curved toward bination with a rotor, of guide apparatus surrounding the rotor, said guide apparatus including a plurality of guide passages, a plurality of receiving channels f r directing the fluid discharged by the rotor the guide passages, and an outer collector casing common to all guide passages for receiving the fluid discharged therepassages being composed of an inner straight walled funnel-shaped portion the cross sectional area of which gradually increases in the direction of flow, and of an outer portion joining said inner portion, said outer portion having lateral straight walls extending transversely to the axis of the rotor and in the same direction as the corresponding straight walls of the inner portion, and inner and the direction of rotation of the rotor to direct the fluid from the outer guide passage portion into the said collector casing, said curved inner and outer walls having radii of curvature measuring, at the entrance of the outer guide passage portion, at least three times the length of the guide passage diameter at the said entrance.

4. In a centrifugal blower or pump, the combination with a rotor, of guide apparatus surrounding the rotor, said guide apparatus including a plurality of guide passages, a-plurality of receiving channels for directing the fluid discharged by the rotor to the guide passages, and an outer collector casing common to all guide passages for receiving the fluid discharged therefrorn, each of said guide passages being composed of an inner straight walled funnel-shaped portion the cross sectional area of which lgradually increases in the direction of flow, and of an outer portion joining said inner portion, said outer portion having lateral straight walls extending transversely to the' axis of the rotor and in the same direction as the corresponding straight walls of the inner portion, and inner and outer walls curved toward the direction of ro- -tation of the rotor to direct the fluid from the outer guide passage portion into the said collector casing, said curved inner and outer walls having radii of curvature measuring, at the entrance of the outer guide passage portion, at least three times the length of the guide passage diameter at the said entrance, and the width of the outer guide passage portion between said curved walls being equal throughout the length thereof.

5. In a centrifugal blower or pump, the combination with a rotor, of guide apparatus surrounding the rotor, said guide apparatus including a plurality of guide passages, a plurality of receiving channels for directing the fluid discharged by the rotor to the guide passages, and an outer collector casing common to all guide passages for receiving the fluid discharged therefrom, each of said guide passages being composed of an inner straight walled funnel-shaped portion the cross sectional area of which gradually increases in the direction of flow, and of an outer portion joining said inner portion, said outer portion having lateral straight walls extending transversely to the axis of the rotor and in the same direction as the corresponding straight walls of the inner portion, and inner and outer walls curved toward the direction of rotation of the rotor to direct the fluid from the outer guide passage portion into the said collector casing, said curved inner and outer walls having radii of curvature measuring, at the entrance of the outer guide passage portion, at least three times cluding a plurality of guide passages, a plurality of receiving channels for directing the fluid discharged by the rotor to the guide passages, and an outer collector casing common to all guide passages for receiving the fluid discharged therefrom, each of said guide passages being composed of an inner straight;v walled funnel-shaped portion the cross sectional area of which gradually increases in the direction of flow, portion joining and of an outer said inner portion, said outer portion having lateral straight walls extending transversely to the axis of the rotor and in the same direction as the corresponding straight walls of the inner portion, and inner and outer walls curved toward the direction of rotation of the rotor to direct the fluid from the outer guide passage portion into the said collector casing, the radii of curvature of said inner and outer curved walls being equal in order to create within the curved portion of the guide passage substantially thesame effect of twist along the inner and outer passage walls.

7. In a centrifugal blower or pump, the combination with a rotor, of guide apparatus surrounding the rotor, said guide apparatus including a plurality of guide passages, a cylindrical chamber free from blades extending around the rotor to collect the fluid discharged from the rotor and having a radial width of at least l/o of the diameter of the rotor, receiving channels for directing the uid from said chamber into the guide passages, and an outer collector casing common to all guide passages for receiving the fluid discharged from the guide passages, each of said guide passages beingfcomposed of an inner straight walled funnel-shaped portion `the cross sectional area of which gradually increases in the direction of flow, and oi' an outer portion joining said inner portion, said outer portion having lateral straight walls extending transversely to the axis of thev rotor and in the same direction as -the corresponding straight walls of the inner portion, and inner and outer walls curved toward the direction of rotation of the rotor to direct the fluid from the outer guide passage portion into' the said collector casing.

8. In a centrifugal blower or pump, the combination with a rotor, of guide apparatus surrounding the rotor, said guide apparatus including a plurality of guide passages, a plurality of receiving channels for directing the fluid discharged by the rotor to the guide passages, and an outer collector casing common to all guide passages for receiving the fluid discharged therefrom, each of said guide passages being composed of an inner straight walled funnel-shaped portion the cross sectional area of which gradually increases in the direction of flow, and of an outer portion joining said inner portion, said outer portion having lateral straight walls extending transversely to the axis of the rotor and in the same direction as the corresponding straight Walls of the inner portion, and inner and outer Walls curved toward' the direction of rotation of the rotor to direct the fluid from the outer guide passage portion into said collector casing, the said inner straight walled guide passage portion being of such a length that the transformation of velocity energy into pressure energy of the fluid enteringl into the guide passage is effected to a major extent in said inner guide passage portion.

9. In a centrifugal blower or pump, the cornbinatlo'n with a rotor, of guide apparatus surrounding the rotor, said guide apparatus including a plurality of guide passages, a plurality of receiving channels for directing the fluid discharged by the rotor to the guidev passages, an outer collector casing common to all'guide passages for receiving the fluid discharged therefrom, and a straight diluser of gradually increasing sectional area formed at the outlet of the collector casing and traversed by the fluid before being discharged from the collector casring, each of said lguide passages being composed of an inner straight walled funnel-shaped portion the cross sectional area of which gradually increases in the direction of flow, and of an outer portion joining vsaid inner portion, said. outer portion having lateral straight walls extending' transversely to the axis of the rotor and in the same direction as the corresponding straight walls of the inner portion, and inner and outer walls curved toward the direction of rotation of the rotor to direct the uid from the outer guide passage portion into said collector casing, the transformation .of velocityy energy into pressure energy of the fluid entering said guide passages being carried out in said guide passages to reduce the velocity of the uid at the entrance into the collector casing to a rate being still higher than the rate of velocity at the outlet of the collector casing, the velocity transformation being completed in said diffuser to the rate of the discharge velocity at the outletof the collector casing.

10. In a centrifugal blower or pump, the combination with a rotor, of guide apparatus surrounding the rotor, said guide apparatus including a plurality of guide passages, a plurality of receiving channels for directing the fluid discharged by the rotor to the guide passages, and an outer collector casing common to all guide passages for receiving the fluid discharged therefrom, each of said guide passages being composed of an inner straight walled funnel-shaped portion the cross sectional area of which gradually increases in the direction of flow, and of an outer portion joining said inner portion, said outer lportion having lateral straight walls extending transversely to the -axis of the rotor and in the same direction as the corresponding straight wallsof the inner portion, and inner and outer Walls curved toward the direction of rotation of f the rotor to direct the fluid from the outer guide passage portion into the said collector casing, the increase of sectional area between the inlet and the outlet of saidguide passages being such that the transformation of velocity energy into pressure energy of the fluid traversing said guide passagesfis 'carried out in the guide passages to reduce the rate of velocity `of the fluid leaving the guide passages'to the rate of discharge velocity at the outlet of the collector casing.

11. In a centrifugal blower or pump, the combination with a` rotor, of guideapparatus surrounding the rotor, said guide apparatus including a plurality of guide passages, a plurality of receiving channels for directing the fluid discharged by the rotor to the guide passages, and an outer collector casing common to` all guide passages for receiving the fluid discharged therewalls curved toward the direction ofrotation of the rotor to direct the fluid from the outer guide passage portion into the said collector casing, the different outer curved guide passage portions -having outlets of successively increasing sectional areas towards the outlet of said collector casing, and the rate of velocity at the passage outlets, considered in the direction of flow in the collector casing, successively decreasing in such manner that the pressure losses resulting in the collector casing between successive passage outlets are at least compensated by the velocity heads existing between such successive outlets.

12. In a centrifugal blower or pump, the combination with a rotor, of guide apparatus surrounding the rotor, said guide apparatus including a plurality of guide passages, a plurality of receiving channels for directing the fluid discharged by the rotor to the guide passages, an outer collector casing common to all guide passages for receiving the fluid discharged therefrom and provided with a discharge opening for the collected fluid, each of saidguide passages being composed of an in'ner straight walled funnel-shaped portion the cross sectional area of which gradually increases in the direction of flow, and of an outer portion joining said inner portion, said outer portion having lateral straight walls extending transversely to the axis of the .rotor and in the same direction as the corresponding straight walls of the inner portion, and inner and outer walls curved toward the direction of rotation of the rotor to direct the fluid from the outer guide passage portion into the said collector casing, and a guide passage delivering fluid into the collector casing in proximity of the discharge opening of said casing and extending substantially parallel to the .axis of said opening, said' guide passage Widening with all sides according to a straight line and having a successively increasing sectional area whereby the velocity of the fluid delivered into the collector casing is equal to the velocity at the discharge opening of the collector casing.

13. In a centrifugal blower or pump, the combination of a rotor, having a discharge end, fluid guide apparatus surrounding said discharge end and forming a chamber for receiving the pressure fluid discharged from said rotor, said guide apparatus having a plurality of straight walled outwardly flaring passages for unidirectionally guiding thefluid through said apparatus, and a casing located outwardly of said guide apparatus forming an annular chamber for collecting said fluid from the outer portions of said passages, said casing being eccentric with respect to the medial plane of the rotor andguide apparatus, said casing having an outlet at one end and merging with its other end with the larger end of one of said straight walled guide passages adjacent said casing outlet, said guide apparatus being sectioned in two equal halves along a plane extending transversely to the axis of said rotor and medially through said rotor and said guide apparatus but eccentrically to said annular chamber with respect to the axial direction ofsaid rotor, 'said annular chamber being situated laterally of said rotor discharge area and the cross sectional area of said chamber gradually increasing in the direction or now or fluid commensurate with the quantity or duid supplied through the guide passages.

14:. In a centrifugal blower or pump, the cornbination of Ya rotor, fluid guide apparatus sur rounding said rotor and providing a chamber for receiving the pressure fluid discharged from said rotor, said guide apparatus having a plurality of continuously outwardly ared straight walled guide passages for unidlrectionally guiding iluid therethrough, and a casing located outwardly of the guide passages for collecting said duid from the outer portions of said passages, said casing having an outlet at one end and merging at its other end with the larger end of one of said straight walled outwardly dared guide passages adjacent said outlet, said guide apparatus being sectioned along a plane extending transversely to the axis of said rotor for exposing the walls of the uid guide apparatus to access for being faced true to the required form.

l5. In a centrifugal blower or pump, the combination of a single-acting rotor, guide apparatus surrounding said rotor and providing a cylindrical chamber for receiving pressure iuid discharged from said rotor, said guide apparatus having a plurality of straight walled outwardly flaring passages therethrough, and a casing located outwardly of said guide apparatus for collecting the fluid from the outer portions of said passages, said casing having an outlet at one end and merging with its other end with the larger end of one of said straight walled guide passages adjacent said outlet, said guide apparatus being sectioned in two equal halves alo'ng a plane extending transversely to the axis of said rotor and medially through said rotor, said apparatus and said casing, each half forming a single piece comprising a section of each of said fluid'gude apparatus, saidv sections being vtruly symmetrical thereby concurrently unidirectionally delivering i said fluid from said receiving chamber /into said collector casing in a balanced flow relative to said plane.

16. I n a centrifugal blower or pump, the combination with `a rotor, oi guide apparatus surrounding the rotor, said guide apparatus including a plurality of guide passages, a plurality of receiving channels for directing the fluid discharged by the rotor to the guide passages, and an outer collector casing common to all guide passages for receiving the iluid discharged therefrom, each of said guide passages being composed of an inner straight walled funnel-shaped portion having straight axes and the cross sectional area of which gradually increases in the direction of flow, and of an outer portion joining said inner portion, said outer portion having lateral straightl walls extending transversely to the axis of the rotor and in the same direction as the corresponding straight walls of the inner portion and inner and outer walls curved toward the direction of rotation of the rotor to direct the iiuid from the outer guide passage portion into the said collector casing, partitions between sucasiioae cessive guide passages, said partitions havinl thickened portions of substantial width owing to the shape of the guide passages, said guide appel ratus being separated in two halves along a plane extending transversely to the axis of the rotor, and connecting means passing through the thickened portions of said partitions for securing the two halves to one another.

17. n centrifugal blower or pump as defined in claim l, wherein the section of now of said guide passages and said receiving channels is of trapezoidal shape.

18. A centrifugal blower or pump as defined in claim l, wherein said receiving channels extendl in such manner with respect to said guide passages that the iiow of fluldvtrom the receiving channels into the inner portion of the guide pessages is symmetrical with respect to the axis of said inner portion.

19. In a centrifugal blower or pump, the combination with a rotor, of guide apparatus surrounding the rotor, said guide apparatus including a plurality of guide passages, a plurality o! receiving channels for directing the fluid discharged by the rotor to the guide passages, and an outer collector casing common to all guide passages for receiving the iluid discharged therefrom, each of said guide passages being composed of an inner straight walled funnel-shaped portion the cross sectional area of which gradually increases in the direction of flow, and of an outer portion joining said inner portion, said outer portion having lateral straight walls extending transversely to the axis of the rotor and in the same direction as the corresponding straight Walls of the inner portion, and inner and outer walls curved toward the direction of rotation of the rotor to direct the fluid from the outer guide passage portion into the said collector casing, said outer curved passage portions having dis# charge sections extending substantially at right angles with respect to the direction o! iiow across thereof.

20. In a centrifugal blower or pump, the combination with a rotor, of guide apparatus surrounding the rotor, said guide apparatus including a plurality of guide passages, a plurality ot receiving channels for directing the tluld discharged by the rotor to the guide passages, and an outer collector casing common to all guide passages for receiving the iluid discharged therefrom, each of said guide passages being composed of an inner straight walled funnel-shaped portion the cross sectional area of which gradually increases in the direction of now, and of an outer portion joining said inner portion, said outer portion having lateral straight walls extending transversely to the axis of the rotor and in the same direction as the corresponding straight walls of the inner portion, and inner and outer walls curved toward the direction of rotation of the rotor to direct the fluid from the outer guide passage portion into the said collector casing, said receiving channels having walls extending relativelyto said inner guide passage portions so as to direct the iluid in a. parallel now according to the axis of said portions into the same.

AIJRED BCHI. 

